<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>表达式二叉树</title>
    <link rel="stylesheet" href="index.css">
</head>

<body>
    <div class="input-box">
        <input type="text">
        <button>生成</button>
    </div>

    <div id="display"></div>

    <div class="layer" id="pre-order-traversal"></div>
    <div class="layer" id="middle-order-traversal"></div>
    <div class="layer" id="post-order-traversal"></div>

    <div id="answer" class="layer"></div>

    <script src="index.js"></script>
</body>

</html>